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"""
bjson/handlers.py
Asynchronous Bidirectional JSON-RPC protocol implementation over TCP/IP
Copyright (c) 2010 David Martinez Marti
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of copyright holders nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
"""
import re
from types import MethodType
from bjsonrpc.exceptions import ServerError
class BaseHandler(object):
"""
Base Class to publish remote methods. It is instantiated by *Connection*.
Example::
class MyHandler(bjson.handlers.BaseHandler):
def _setup(self):
# Initailize here.
self.c = 0
def echo(self,text):
print text
self.c += 1
def getcount(self): return c
Other members:
**public_methods_pattern**
RegEx string that returns True if the method name is suitable for
publishing. Defaults to r'^[a-z]\w+$'
**nonpublic_methods**
List of string containing names that shouldn't be published (even
if they are in the format required by the RegEx). Defaults to
["close","_factory","add_method","get_method"]
"""
public_methods_pattern = r'^[a-z]\w+$'
# Pattern to know which methods should be automatically published
nonpublic_methods = [
"close",
"_factory",
"add_method",
"get_method",
]
# List of method names that never should be published
@classmethod
def _factory(cls, *args, **kwargs):
"""
*New in bjsonrpc v0.2.1*
Classmethod aimed to create flavoured instances of BaseHandler.
When you create a new connection you may want to give the constructor
a set of specific arguments. Use this classmethod to do that:
conn = bjsonrpc.connect(handler_factory=MyHandler._factory("my flavoured one"))
Later, whenever the class is instantiated, the BaseHandler.setup
method will receive the arguments passed to factory.
The original idea for this feature is from Paul Pietkiewicz *(pawel.pietkiewicz (at) gmail.com)*
"""
def handler_factory(connection):
handler = cls(connection, *args, **kwargs)
return handler
return handler_factory
def __init__(self, connection, *args, **kwargs):
self._conn = connection
if hasattr(self._conn,"connection"):
self._conn = self._conn.connection
if hasattr(self._conn,"_conn"):
self._conn = self._conn._conn
self._methods = {}
for mname in dir(self):
if re.match(self.public_methods_pattern, mname):
function = getattr(self, mname)
if isinstance(function, MethodType):
self.add_method(function)
self._setup(*args,**kwargs)
def _setup(self,*args,**kwargs):
"""
Empty method to ease inheritance. Overload it with your needs, it
will be called after __init__.
"""
pass
def _shutdown(self):
"""
Internal method called when the handler is going to be destroyed.
You should add cleanup code here. Remember to call the parent
function.
"""
self.close()
def close(self):
"""
Cleans some variables before the object is freed. close is called
manually from connection whenever a handler is going to be deleted.
"""
self._methods = {}
self._conn = None
def add_method(self, *args, **kwargs):
"""
Porcelain for publishing methods into the handler. Is used by the
constructor itself to publish all non-private functions.
"""
for method in args:
if method.__name__ in self.nonpublic_methods:
continue
try:
assert(method.__name__ not in self._methods)
except AssertionError:
raise NameError("Method with name %s already in the class methods!" % (method.__name__))
self._methods[method.__name__] = method
for name, method in kwargs.items():
if method.__name__ in self.nonpublic_methods:
continue
try:
assert(name not in self._methods)
except AssertionError:
raise NameError("Method with name %s already in the class methods!" % (method.__name__))
self._methods[name] = method
def get_method(self, name):
"""
Porcelain for resolving method objects from their names. Used by
connections to get the apropiate method object.
"""
if name not in self._methods:
raise ServerError("Unknown method '%s'" % name)
return self._methods[name]
class NullHandler(BaseHandler):
"""
Null version of BaseHandler which has nothing in it. Use this when you
don't want to publish any function.
"""
pass